Multiplexed SERS detection of DNA targets in a sandwich-hybridization assay using SERS-encoded core–shell nanospheres

Abstract

In this study, a class of surface enhanced Raman spectroscopy (SERS) encoded core-shell nanospheres was synthesized as nano-SERS-tags for detecting specific DNA targets based on the sandwich hybridization assays. These core-shell nanospheres were synthesized by first depositing a layer of Ag-NPs (nanoparticles) onto the poly(styrene-co-acrylic acid) core and then the formation of a layer of uniform silica as the outer shell. The Ag-NPs served as SERS substrates with Raman active molecular probes adsorbed onto the Ag-NPs as indicative SERS molecular barcodes, and the silica coating shell was used for protecting the Ag-NPs and the Raman molecules from the exterior chemical and biological interference. The silica surfaces of nano-SERS-tags were further conjugated with probe DNA (pDNA) (nano-SERS-probes). The detection of single-stranded oligonucleotide (ssDNA) targets was successfully accomplished using the nano-SERS-probes in a chip-based sandwich hybridization assay in a mixed ssDNA target solution. The as-prepared nano-SERS-probes exhibited high chemical stability during the laser SERS experiments and the results were reproducible after a long-term storage. At least four different tags (a four ''color'' system) were quantitatively differentiated when simultaneously applied in the assays, indicating an excellent multiplexing potential of the method. Therefore, the as-prepared nano-SERS-probes are suitable for high specific detection of biomolecules with high sensitivity and remarkable multiplexing capability associated with the SERS method.

Multiplex DNA Biosensor for Viral Infection Diagnosis Using SERS Molecular Sentinel-on-Chip

“…By profiling gene expression in peripheral blood in response to respiratory viral infection, a recent study showed that these two genes are among a set of host genes differentially expressed upon viral infection [27][28][29]. It is noteworthy that before our work, various SERSbased multiplex DNA detection techniques have been reported [30][31][32][33][34][35][36]. However, most of these techniques require multiple hybridization and/or washing steps or target sequences labeling.…”

SERS Nanosensors and Nanoreporters: Golden Opportunities in Biomedical Applications

“…Recently, we demonstrated a unique label‐free SERS‐based multiplex DNA biosensor using molecular sentinel‐on‐chip (MSC) technique (Figure ) . Compared to other SERS‐based multiplex DNA detection methods, our method is free of target sequence labeling and only requires a single incubation step without the need of post‐incubation washing, thus making it simple‐to‐use, with short runtime and low reagent cost. The detection mechanism of the MSC technique is based upon the decrease of SERS intensity when Raman labels attached at 3′‐ends of MS nanoprobes are physically displaced from the SERS plasmonic chip's surface upon DNA hybridization .…”

Sensitive DNA detection and SNP discrimination using ultrabright SERS nanorattles and magnetic beads for malaria diagnostics

“…SERS-based DNA detection has been investigated widely (Cao et al, 2002; Fabris et al, 2007; Faulds et al, 2008; Gao et al, 2013; He et al, 2011; Hu et al, 2010; Kang et al, 2010; Li et al, 2012; Li et al, 2013b; Ngo et al, 2014a; Ngo et al, 2014b; Ngo et al, 2013, 2015; Qi et al, 2014; Sun et al, 2007; Xu et al, 2015). The Mirkin group developed gold nanoparticle probes labeled with oligonucleotides and Raman-active dyes for multiplex detection of DNA (Cao et al, 2002) with an unoptimized detection limit of 20 fM.…”